Its county seat is San Antonio, the second-most populous city in Texas and the seventh-largest city in the United States. Bexar County is included in the San Antonio-New Braunfels, TX metropolitan statistical area. Bexar county includes Government Canyon state natural area in northwestern part of the county.
If the screen width is 7 feet and the projector's throw ratio is 2.0 - 2.4:1 (because projectors have zoom lenses, they also have a range of throw ratios) then you can place your projector anywhere from 14 to 16.8 feet away from the screen.
How a vision screening is performed. During a vision screening, you will typically be asked to sit or stand 20 feet away from the eye chart. In instances where the optometrist's office is not 20 feet long, the chart may be located behind you and a mirror may be placed on the opposite wall to simulate a distance of 20 feet.